A rapidly spreading brush fire in Yosemite National Park grew into one of California's worst wildfires on Saturday, prompting evacuation orders for thousands of people and knocking out electricity to more than 2,000 homes and businesses.

According to the California Department of Forestry and Fire Protection, or Cal Fire, the Oak Fire began Friday afternoon southwest of the park near the hamlet of Midpines in Mariposa County. By Saturday, it grew to about 15 square miles (38 square kilometers). It erupted as firefighters progressed against a previous fire that had burnt to the edge of a grove of gigantic sequoias in the southernmost portion of Yosemite National Park.

A spokesperson for the Sierra National Forest, Daniel Patterson, said that on Saturday, evacuation orders were issued for more than 6,000 individuals living in a sparsely populated rural area spanning several miles.

Patterson stated that more than 400 firefighters, together with helicopters, other aircraft, and bulldozers, were battling the wildfire under harsh conditions, including high temperatures, little humidity, and bone-dry vegetation caused by the worst drought in decades.

Cal Fire issued a statement describing the Oak Fire's activity as "extreme with frequent runs, spot fires, and group torching" on Saturday, stating that "explosive fire behavior is challenging firefighters."

On Saturday morning, Cal Fire reported that the fire had destroyed ten residential and business properties, damaged five others, and threatened 2,000 more structures. The fire caused several road closures, including the closure of Highway 140 between Carstens Road and Allred Road, one of the primary ways into Yosemite.

As a result of climate change, the West has become significantly warmer and drier over the past three decades, which has led to more extensive and deadlier wildfires in California. According to scientists, the weather will continue to become more extreme, while wildfires will become more common, destructive, and unpredictable.

"The fire is spreading rapidly. Yesterday, this fire was spewing embers up to two kilometers ahead of itself, according to Patterson. "The fire conditions are exceptional." The origin of the fire was being investigated.

Pacific Gas & Electric stated on its website that more than 2,600 homes and businesses in the area were without electricity as of Friday afternoon, with no indication of when power would be restored. "PG&E cannot access the affected equipment," stated the utility.

On Friday, a shoeless older man attempting to leave the fire wrecked his car into a ditch in a restricted area and was assisted by firefighters. He has transported away from the scene without any apparent injuries. Several other homeowners remained in their houses while the fire burned Friday night.

Firefighters have made substantial headway against a blaze that erupted in Yosemite National Park and spread to the Sierra National Forest.

Friday, 79 percent of the Washburn Fire was contained after consuming approximately 7.5 square miles (19.4 square kilometers) of the forest. It was one of the largest fires in California that year, along with the 9-square-mile Lost Lake Fire in Riverside County that was extinguished in June (23 square kilometers).

The fire broke out on July 7 and prompted the closure of Yosemite's southern gate and the evacuation of the village of Wawona as it burnt on the outskirts of Mariposa Grove, home to hundreds of gigantic sequoias, the world's most giant trees by volume.

According to the park's website, Wawona Road is expected to reopen on Saturday.